Electric motors have previously been proposed with oil slinger discs rotating with the rotor shaft to cause oil in the bearing compartment to be retained in that bearing compartment, e.g., in U.S Pat. No. 3,885,176. A similar principle has been suggested in horizontal shaft motors, as in U.S. Pat. No. 2,950,402, with a rotating disc or outwardly concave cone to centrifugally sling contaminants to keep them from the interior of the motor. A similar construction has also been suggested for vertical shaft motors for drip-proof construction, as in dishwashers, as suggested in U.S. Pat. Nos. 4,287,662 and 4.535,262. A multi-apertured rotating slinger disc has also been suggested in U.S. Pat. No. 4,358,303 as a debris screen. Where a motor is to be operated in an explosive atmosphere, explosion-proof designs have been suggested wherein atmosphere can circulate through the motor but has to pass through a flame arrester of axially spaced, rotating radial plates to cool any explosive same, as in U.S. Pat. No. 2,736,826. Where a totally enclosed motor-is required, U.S. Pat. No. 2,769,105 suggests an air-to-air heat exchanger with a labyrinth seal to prevent interchange of interior to exterior air.
All of these prior solutions have been for fairly large motors, e.g., at least 1/4 horsepower Where a subfractional horsepower fan motor is desired, e.g., 4 to 7 watts output and 7 to 10 watts input. this requires a high efficiency motor. Also, such motors may be required in environments which need to be hosed down, e.g., for ten minutes each day for sanitary reasons. If packings or gaskets are utilized around the motor shaft to keep out the entrance of such water splashing. the friction caused by such packings or gaskets is normally so high that the subfractional horsepower motor will fail to start.